As pointed out in the aforementioned copending applications the deposition of material from a vapor phase onto a substrate is well known in the coating art and in the field of surface transformation of a substrate. Generally speaking, a body of the material to be transferred to the substrate is heated in the region of this substrate and transformed first into a molten state and then into a vapor state. The material thus undergoes two phase transformations, namely, the transformation from the solid phase to the liquid phase and then from the liquid phase to the vapor phase.
The coating is generally effected in a vacuum and usually a relatively high vacuum must be drawn to permit transfer of vapors from the source to the substrate.
Earlier systems may use induction heating to effect the aforementioned phase transformation.
In the aforementioned applications, I have described an improvement over these earlier systems in which a substance, generally a metal may be transferred to a substrate also in a vacuum environment, utilizing an electrode as the source of the material, by the process which involves striking a more or less stable arc between the molten material and a counterelectrode to thereby generate the vapors.
Coating in this manner can be effective to apply anticorrosion, protective, decorative, conductive, semiconductive or other coatings upon a substrate and I am also able to form compounds on the substrate between materials deposited and substances on the substrate or two materials to be deposited. For example the last mentioned of the three applications describes also the formation of carbides, borides, silicides, nitrides and silicon carbides.